Probing of 25-µm-diameter micro-bumps is a step towards 3D ICs

Breakthrough probing results, achieved with CM300 probe system, are seen as an enabling technology for progress in the 3D IC market

Cascade Microtech, wafer-probing specialist, and Belgian research centre imec, have announced breakthroughs in probing stacked integrated circuits (3D-SICs). Cascade partnered with imec to successfully probe 25-µm-diameter micro-bumps on a wide I/O test wafer with its fully-automated CM300 probe solution using an advanced version of Pyramid Probe technology.

The 3D semiconductor market (including 3D-SIC, 2.5D interposer, and 3D WLCSP) is expected to represent 9% of the total semiconductor value by 2017, according to analysts Yole Developpement. Logic 3D SoC/SiP (including interposer chips, APE, CPU, FPGA, wide IO memory, etc.) will be the biggest industry using 3D platforms in the next few years. 3D applications will emerge in high-performance computing, and electronic markets such as nanotechnology and medical applications, which will benefit from the high-density integration that 3D technology offers.

Through-Silicon Vias (TSV) used in 3D-SICs, shorten interconnects between logic elements, thus reducing power while increasing performance. Within imec’s 3D integration research program, industry leaders are jointly developing design, manufacturing, and test solutions to bring this new technology to high-volume manufacturing.

Cascade Microtech’s CM300 flexible on-wafer measurement system was designed to deliver superior positioning accuracy and repeatable contact, offering a level of precision that supports both shrinking pad sizes and pitch roadmaps. The CM300 captures the true electrical performance of devices with high-performance capabilities that include low leakage and low noise. As a comprehensive probing solution employing the latest advances in Pyramid Probe technology, the CM300 has proven to meet the fine-pitch (40-µm area array), low-force (< 1gf/tip) advanced probing requirements of 3D-SICs.

“I believe together we’ve achieved a first in the industry,” said Erik Jan Marinissen, Principal Scientist at imec in Leuven, Belgium. “We are able to hit 25µm-diameter micro-bumps with a high level of accuracy due to the probe-to-pad alignment features of Cascade Microtech’s CM300. And advances in their Pyramid Probe technology have enabled us to probe micro-bumped wafers with 40/50µm pitch according to the JEDEC Wide-I/O Mobile DRAM standard.”